"no implicit conversion of ActiveSupport::SafeBuffer into Array" if render simple_fields_for in trailblazer cell

[havran]

Steps to reproduce

I use simple_form in cells and i want render simple_fields_for on different cell as main form.
In code on which error is raised is variable output as array (which is maybe not wanted here?).
This is maybe not ActiveSupport::SafeBuffer problem but simple_form problem?

Expected behavior

Its should render html output.

Actual behavior

Raise error: "no implicit conversion of ActiveSupport::SafeBuffer into Array"

# block in fields_for_nested_modelactionview (5.0.1) lib/action_view/helpers/form_helper.rb

            options.fetch(:include_id, true)
          }
          @template.fields_for(name, object, fields_options) do |f|
            output = @template.capture(f, &block)
            output.concat f.hidden_field(:id) if output && emit_hidden_id && !f.emitted_hidden_id? # <<< error is raised on this line
            output
          end
        end
        def nested_child_index(name)

System configuration

Rails version: 5.0.1

Ruby version: 2.3.1

[al2o3cr]

From the error message, it sounds like the @template.capture(f, &block) line is returning an instance of Array rather than the expected buffer.

To troubleshoot this further is going to require either an minimal application that reproduces the error (ideal) or at least the source for the template that's triggering this error.

[rails-bot]

This issue has been automatically marked as stale because it has not been commented on for at least three months.
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